US1175461A

US1175461A - Ejector.

Info

Publication number: US1175461A
Application number: US83647914A
Authority: US
Inventors: Maurice Leblanc
Original assignee: Societe Anonyme pour L Exploitation des Procedes Westinghouse Leblanc SA
Current assignee: Societe Anonyme pour L Exploitation des Procedes Westinghouse Leblanc SA
Priority date: 1914-05-05
Filing date: 1914-05-05
Publication date: 1916-03-14
Anticipated expiration: 1933-03-14

Description

M. LEBLANC.

EJECTOR.

APPLICATION FILED MAY 5. 1914.

Pat nted Mar. 14,1916.

INVENTOR:

MAURICE LEBLANC, 0F VAL-SUB-SEINE, CR-OISSY, FRANCE, ASSIGNOR 'JJO SOCIETE ANONYME POUR LEXPLOITATION DES PROCEDES WESTINGHOUSE-LEBLANC, OF

PARIS, FRANCE.

EJ'ECTOR.

Specification of Letters Patent.

Patented Mar. 14, 1916.

To all whom it may concern:

Be it known that I, MAURICE LEBLANG, a citizen of the Republic of France, residing at Val-sur-Seine, Croissy, Seine-et-Oise, France, have invented a new and useful Improvement in Ejector-s, of which the following is a specification.

This invention relates to ejectors and particularly to ejectors operated by elastic fluid for compressing air or other elastic fluid from a region of low pressure to a region of high pressure.

An object of the invention is to produce a new and improved elasticfluid actuated ejector, which is capable of Withdrawing elastic fluid, such as air or non-condensable vapors or gases, from a container such as a condenser, in which a. relatively low pressure is maintained, and of compressing the fluid so withdrawn to a relatively high pressure such, for example, as atmospheric pressure.

A further object is to produce a multistage ejecting apparatus, which is simple in construction and is capable of operating with a minimum amount of motive or impelling fluid, hereinafter termed steam, in compressing an elastic fluid such as air from a relatively low to a relatively high pressure.

These and other objects are attained by means of apparatus embodying the features herein described and illustrated in the drawings accompanying and forming a part hereof.

In the drawings, Figure 1 is a more or less diagrammatic illustration of an ejector apparatus embodying my invention. Fig. 2 is a vertical sectional view of a modified form of ejector apparatus embodying my invention. Fig. 3 is a fragmental sectional view showing a modification in the arrangement of nozzles which may be employed in the apparatus illustrated in Fig. 2.

It has been proposed to employ ejectors as vacuum pumps for withdrawing noncondesable fluids, such as air, from condensers. This has never been successfully accomplished wher steam or other elastic fluid under pressure has been emplo ed as the impelling or ejecting agent. Ejectors operating as vacuum pumps must compress air or non-condensable vapors. withdrawn from the condenser, from an absolute pressure of approximately of a pound to atwith high efficiency as a vacuum pump for condensers it is therefore necessary to so proportion and arrange the motive fluid or steam delivery nozzles and the interior passages of the ejector that they will so cooperate in accomplishing the entrainment of the fluid to be ejected, that each portion or element of the ejector will perform its function with maximum efliciency. In order to accomplish this, the entrainment of the fluid to be ejected must take place Without shock or the production of eddy currents or swirls in either the impelling steam or ejected fluid; the impelling steam must be introduced into the ejector at a high velocity capable of effecting the necessary pressure conversion, and it must be so introduced that it will not be subjected to shock or an abrupt expansion as it enters the interior passages of the ejector. The apparatus herein illustrated as an embodiment of my invention has been developed with these facts in mind, and is capable of operating efliciently as a vacuum pump for condensers.

Referring to Fig. 1: The apparatus illustrated includes two axially alined ejectors a and I), both of which are provided with steam delivery nozzles arranged to operate in parallel on the fluid to be ejected. The ejector acomprises a convergent divergent difiuser tube 7, provided with an inlet port 8, and a series of steam or motive fluid delivery nozzles which are constructed and arranged as set forth in my Patents Nos. 1,001.153 and 1.001,]54 of August 22, 1911. As illustrated, the series of nozzles includes a central nozzle 9 which is axially alined with the tube 7 and receives fluid from a steam chamber 10 provided with an inlet port adapted to communicate with a suitable source of steam under pressure. The series of nozzles also includes

nozzles

9 and 9 which are arranged in concentric rings or crowns around the nozzle 9. The nozzles 9 are shown as communicating with the s eam chamber 10 and they project below the nozzle 9 a suflicient distance to insure the entrainment by the jet of steam issuing from the nozzle 9 of all the fluid to be eject-v ed which it is capable of entraining. In other words, the nozzles 9 project below the nozzle 9 a suflicient distance to prevent the jet of steam issuing from the nozzle 9 from being screened by the jets issuing from the nozzles 9. The ring of nozzles 9" surrounds the nozzle 9' and projects below their outlet ends a suflicient distance to prevent screening of the jets issuing from them. A separate steam chamber 11 is provided for the nozzles 9 and is provided with a separate inlet port adapted to communicate with any suitable source of steam supply. It will, of course, be understood that the spacing of the nozzles 9' and 9 is such as to insure a free flow of fluid to be ejected to each nozzle of the series, so that each separate steam jet will operate eflicie-ntly in entraining fluid. In Fig. 1 the inlet port 8 communicates with the converging portion of the tube 7 at a point adjacent to the steam delivery nozzles so that the condenser or apparatus to be evacuated will be in free and open communication with the combining portion of the tube, or that portion into which the steam jets are delivered.

In order to reduce the fluid friction to a minimum, it is essential that the combzned stream of steam, made up of the separate ets discharged from the

nozzles

9, 9 and 9", conforms as nearly as possible to the internal contour of the passage through which it flows. For this reason, I have shown the

nozzles

9 and 9" inclined inwardly so that their axes produced meet at a point within the axis of the tube 7, or the produced axis of the nozzle 9. The point of convergence of'the axes of the nozzles is preferably so selected that the jets of fluid discharged from the nozzles 9" are substantially parallel to the adjacent or converging wall of the tube 7. With this arrangement the nozzles discharge annular sheaths of steam which combine to form a stream having an external contour wh ch substantially conforms to the internal contour of the converging portion of the tube 7 and which passes through the tube without producing eddy or swirl currents and with a minimum amount of fluid friction.

In order to prevent the formation of eddy currents in the steam issuing from the

nozzles

9, 9' and 9", it is essential that these nozzles, expand the steam, in its passage through them, to substantially the pressure normally encountered at the inlet of the tube 7. These nozzles are therefore expansion nozzles having divergent walls. The ejector 6 comprises a convergent divergent tube 12, and an annular nozzle 13, which communicates with a steam chamber 14, receiving steam from any suitable source of steam supply. The inlet or converging portion of the tube 12 communicates with the outlet or diverging end of the tube 7 and, as illustrated, the nozzle 13 surrounds the end of the tube 7. It will be apparent that the nozzle 13 may be replaced by an annular series of nozzles and that they may be located around the end of the tube 7 without actually surrounding it. It is, however, important that the steam delivery nozzles of the ejector b shall'be so located as not to impede the flow of fluid through the passages of the combined ejector. In addition to this, it is necessary to so arrange the steam .delivery nozzles or nozzle 13 of the ejector 7) that the sheath shaped jet issuing therefrom will travel in a path substantially parallel to the adjacent portion of the tube 12. As illustrated, the nozzle 13 is inclined in- .wardly so that it delivers a substantially conical sheath of steam to the tube 12 which, wh le it travels longitudinally through the tube, substantially conforms to the contour of the adjacent or converging wall of the tube.

In theapparatus illustrated in Fig. 1, I have shown by dotted lines, that the convergence of the steam delivery nozzles of both ejectors is such that thepoint of convergence of the produced axes of the nozzles is at a point below the throat of the cor responding diffuser tube, or below the converging portion of the tube. Such an arrangement has been found to give excellent results, but the important feature in the arrangement of the nozzles is that they be so arranged that the combined stream of steam issuing from the set of nozzles in each ejector will substantially conform in external contour to the internal contour of the wall of the passage or tube into which it is delivered. It is also necessary to so constructthe nozzle or nozzles of the ejector b that the steam will be expanded in its passage through it or them to substantially the pressure encountered at the inlet end of the tube 12. In other words, it is essential to provide the ejector b with one or more divergent or expanding fluid delivery nozzles for the reasons pointed out in connection with the description of the steam delivery nozzles of the ejector a. \Vith this arrangement of apparatus, the steam issuing from the nozzles or nozzle 13 operates with maximum efficiency in entraining the fluid del vered to the tube 12 from the ejector a.

The operation of the apparatus is as follows: In starting the ejector, steam under pressure is delivered to the chamber 14 and consequently to the nozzle or nozzles 13. Steam may also be delivered to all of the nozzles of the ejector a. but I preferably deliver steam at a pressure above normal to the nozzles 9 and. after a reduction in pressure has taken place within the tube 7. I gradually reduce the flow of steam through the nozzles 9" until the normal flow is reached and I then deliver steam to the

nozzles

9 and 9 and gradually increase the flow of steam through these nozzles until the normal flow is obtained. This method of starting is fully described in my Patent 1,07 9,134 of November 18, 1913. The air to be ejected is therefore entrained by each of the separate jets of fluid issuing from the nozzles of the ejector a. After the entrainment is accomplished, the separate jets combine into a more or less solid stream and pass through the throat or narrowest portion of the tube 7. The velocity of the combined stream is converted into pressure as the stream traverses the divergent portion of the tube 7 and consequently it is delivered at increased pressure and with reduced velocity to the inlet end of the tube 12. The steam issuing from the divergent nozzles or nozzle 13 is moving at a high velocity, greater than that of the combined stream issuing from the tube 7, and consequently entrains the fluid from the ejector a as it enters the ejector b. The fluid then passes in a converging stream through the converging portion of the tube 12, where the entrainment is completed, and the velocity of the fluid is converted into pressure as it traverses the divergent portion of the tube 12. The velocity of the steam issuing from the nozzle or nozzles 13 will, of course, be suflicient to provide the necessary pressure conversion for discharging the combined fluid from the divergent end of the tube 12.

In Fig. 2, I have illustrated a modified form of ejecting apparatus which includes two ejectors, c' and d operating in series and in which the motive. fluid delivery nozzles of the separate ejectors operate in parallel on the fluid to be ejected, as described in connection with the apparatus illustrated in Fig. 1. The ejector 0 includes a convergent divergent tube 15, the converging end of which communicates with a combing chamber 16, which is provided with a port 17, adapted to communicate with apparatus to be evacuated. A series of nozzles 18 projects into the combining chamber 16 in such a way that the combined stream of fluid, made up of the separate steam jets issuing from them, enters the diffuser tube 15 after having traversed a portion of the chamber 16. As illustrated, these nozzles communicate with a steam chamber 19, which receives steam from any suitable source and the nozzles are so arranged that the combined stream of steam issuing from them will substantially conform in external contour to the internal contour of the inlet end of the diffuser 15. The nozzles are arranged in a crown, as described in connection with Fig.

1, with the outer nozzles of the crown projecting below the inner nozzles so as to prevent screening, as above described. The outlet of the tube 15, communicates with the inlet of the ejector (Z, which comprises a convergent divergent tube 20 and an annular series of nozzles 21 arranged around the outlet of the tube 15, and communicating with a steam chamber 22, which receives steam from any suitable source through a separate inlet port. These nozzles are inclined inwardly so that the stream of steam issuing from-them conforms in external contour substantially to the internal contour of the converging portion of the tube 20. These nozzles are also divergent nozzles arranged to expand the steam issuing from them to substantially the pressure of the fluid normally existing at the inlet of the diffuser 20. The nozzles are also spaced so that the jet of steam issuing from each nozzle will entrain all of the fluid to be ejected which it is capable of entraining.

In Fig. 3, I have shown a modification of the invention in that the ejector (l or the second ejector of the series is provided with two rings of nozzles 23 and 2 T. The inner ring of nozzles projects below the outer ring to prevent screening, as above described, and both rings of nozzles are inwardly inclined so that the stream of steam formed by the separate jets issuing from them will, conform substantially in external contour to the internal contour of the adjacent portion of the diffuser. The spacing of the nozzles 23 is such as to insure the delivery of sufficient fluid, discharged from the preceding ejector, to the outer row of nozzles 24,so that these nozzles will operate effectively as fluid entraining agents. The outlet of the diffuser tube 20 of each ejector shown in Figs. 2 and 3 communicates with the atmosphere or with the receptacle into which the fluid ejected is to be compressed, and the operation, of each of the ejectors is similar to that described in connection with the ejector illustrated in Fig. 1. I

I claim asmy invention:

1. The combination of two ejectors connected in series the first ejector opening directly into the second ejector, means for supplying motive fluid separately to each of said ejectors and means for causing the direction of flow of motive fluid in the first ejector and of motive and entrained or exhausted fluids in the second ejector to follow that of the converging portions of said ejectors.

2. The combination of two inter-connected ejectors the first ejector opening directly into the second ejector each of said ejectors having a plurality of nozzles and means for supplying motive fluid separately to the nozzles in each of said ejectors said nozzles being so disposed that the direction of flow of motive fluid in the first ejector and of motive and entrained or exhausted fluids in the second ejector will follow that of the converging portions of said ejectors.

3. The combination of two ejectors in alinement the first ejector opening directly into the second ejector each of said ejectors having a plurality of rings of nozzles arranged in tiers, means for supplying motive fluid separately to the nozzles in said ejectors said nozzles being so disposed that the direction of flow of motive fluid in the first ejector-and of motive and entrained or exhausted fluids in the second ejector wili follow that of the converging portions of said ejectors.

4. The combination of two ejectors each having a converging and a diverging portion the diverging portion of the first e ector opening directly into the converging portion of the second ejector, the first ejector having a plurality of rings of nozzles arranged in tiers and the second ejector a plurality of nozzles interposed between the wall of the diverging portion of the upper ejector and that of the converging portion of the lower ejector, means for supplying motive, fluid to the nozzles in said ejectors said nozzles being so disposed that the direction of flow of motive fluid in the first ejector and of motive and entrained or exhausted fluids in the second ejector will follow that of the converging portions of said ejectors.

The combination of two ejectors each.

verging and a diverging portion, each of said ejectors having a plurality of rings of nozzles arranged in tiers, means for supplying each ring of nozzles separately with motive fluid said nozzles being so disposed that the direction of flow of motive fluid and of entrained or exhausted fluids will follow the direction of the converging portions of said ejectors.

7. The combination of two ejectors each having a converging and a diverging portion the first ejector opening directly into the second ejector the first of said ejectors having a plurality of rings of divergent nozzles arranged in tiers, means for supplying certain of said rings of nozzles with motive fluid separately from the other of said rings of nozzles, the second ejector having a plurality of nozzles supplied with motive fluid separately from the nozzles in the first ejector and means for causing the direction of flow of motive fluid in the first ejector and of motive and entrained or exhausted fluids in the second ejector to follow that of the converging portions of said ejectors.

8. The combination of two ejectors, each having a converging and a diverging portion, the diverging portion of the first ejector opening directly into the converging portion of the second ejector, the first ejector having a plurality of rings of nozzles, means for supplying certain of said rings of nozzles with motive fluid separately from the other of said rings of nozzles, the second ejector havinga plurality of divergent nozzles interposed between the wall of the diverging portion of the upper ejector and that of the converging portion of the lower ejector supplied with motive fluid separately from the nozzles in the first ejector the direction of all the nozzles in both ejectors being such that the flow of motive fluid in the first ejector and of motive and entrained or exhausted fluids in the second ejector is the same as that of the converging portions respectively of said ejectors.

9. The combination of two ejectors each having a converging and a diverging portion and both provided with a plurality of nozzles the diverging portion of the first ejector opening into the converging portion of the second ejector and means for supplying motive fluid separately to the nozzles of each of said ejectors.

10. The combination of two ejectors connected in series each having a converging and a diverging portion and both provided with a plurality of nozzles and means for supplying motive fluid separately to the nozzles of each of said eiectors said nozzles being so disposed that the direction of flow of fluid through said ejectors will follow the direction of the converging portions of said e ectors.

11. In an ejecting apparatus, the combination of an ejector comprising a diffuser tube having a fluid inlet at the converging end thereof, a series of motive fluid delivery nozzles projecting into the tube at the inlet end thereof, so arranged as to direct the motive fluid issuing therefrom in lines substantially parallel to the converging wall of the tube, and a second ejector axially alined with the first ejector and comprising a convergent divergent diffuser tube, the inlet end of the converging portion of the tube communicating with the discharge end of the first mentioned tube, and a series of divergent motive fluid delivery nozzles surrounding the discharge end of the first tube.

12. In an ejecting apparatus, the combination of an ejector comprising a convergent divergent tube'having an inlet at the converging end and terminating in a fluid discharge port at the diverging end thereof, and a series of divergent nozzles for delivering motive fluid to the converging portion of the tube so arranged that the sepaate jets of fluid issuing from the nozzles are projected in lines substantially parallel to the converging all of the tube while the direction of flow of the combined stream of fluid is axial with relation to the tube, and a second ejector comprising a convergent divergent tube axially alined with the first tube and having its convergent portion in direct communication with the discharge port thereof. and an annular series of divergent motive fluid delivery nozzles located within the converging portion of the second tube and around the discharge port of the first tube, said nozzles being so arrangedthat the flow of fluid from the first to the second tube is substantially unimpeded and so that each nozzle discharges a stream of motive fluid substantially parallel to the converging wall of the second tube.

13. In an ejecting apparatus, the combination of a convergent divergent tube, having a fluid inlet communicating with the converging portion of the tube, a divergent nozzle projecting into the converging portion of the tube and communicating with a source of motive fluid supply, a second convergent divergent tube axially alined with the first tube and having its converging portion in communication with the divergent portion of the first tube, a series of divergent motive fluid delivery nozzles located in the converging portion of the second tube so arranged that the flow of fluid from the first to the second tube is substantially unimpeded and so that the separate streams of motivefluid issuing therefrom traverse lines substantially parallel to the converging portion of the second tube.

14:. In an ejecting apparatus, a diffuser tube, having an inlet for fluid to be exhausted communicating with the converging end thereof, a nozzle for delivering a stream of motive fluid, moving at a high velocity, through said tube, a convergent divergent diffuser tube, axially alined with the first deliveryinozzle for delivering a stream of motive fluid at a high velocity through said tube, a second convergent divergent tube communicating with the divergent end of the first tube and axially alined therewith, and a divergent nozzle for delivering motive fluid at a high velocity to the second tube located adjacent to the end of the first tube.

16. An ejecting apparatus, comprising a plurality of axially alined convergent divergent tubes, and means located beween the ends ofadjacent tubes for delivering a converging stream of motive fluid, said means being so located as to provide a substantially unobstructed passage for fluid through the alined tubes.

In testimony whereof I have hereunto subscribed my name this 21st day of April 1914.

MAURICE LEBLAXC. Vitnesses HANSON C. Coxn, GABRIEL BELLIARD.